Newark Mayor Cory Booker is shown in this July file photo. He leads all his potential Senate rivals in a new poll. John O'Boyle/The Star-Ledger

TRENTON — Newark Mayor Cory Booker dominates his potential Democratic primary opponents for U.S. Senate in 2014, according to a poll released today by a San Francisco-based advocacy group that supports Booker.

The poll of 1,170 registered New Jersey Democrats — conducted for PowerPAC.org by the Merriman River Group — finds Booker leads incumbent U.S. Sen. Frank Lautenberg (D-N.J.) 48 percent to 21 percent.

If Lautenberg, who turns 89 today, decides to retire, Booker has a two-to-one lead over the combined totals of three other potential candidates listed: Rep. Frank Pallone (D-6th Dist.), Rep. Rob Andrews (D-1st Dist.) and state Senate President Stephen Sweeney (D-Gloucester).

“Specifically, what we’re trying to understand better is what happens without Lautenberg in the race,” said Julie Martinez Ortega, the group’s vice president of policy and advocacy.